1. Field of the Invention
The present invention relates to a chucking table for chucking and holding a flexible substrate, which is employed in processes for manufacturing electric apparatuses and the like.
Priority is claimed on Japanese Patent Application No. 2003-102902, filed Apr. 7, 2003, the content of which is incorporated herein by reference.
2. Description of Related Art
Organic EL (electroluminescent) elements, which enable the manufacture of display devices that are thinner than liquid crystal displays, are remarked as a next generation technology. By arranging organic EL elements on a flexible plastic sheet, a thin and flexible display device, similar to a piece of paper, can be manufactured. In the processes for manufacturing organic EL (electroluminescent) elements or a TAB (Tape Automated Bonding), a technical means is employed in which luminescent layers and patterned circuits are formed by discharging droplets, such as of luminescent material or conductive material, toward a substrate or the like which is placed on a table device, using an ink-jet method. In order to hold a substrate or the like on the table device in this process, a porous body is provided into the table device so that a substrate can be held by chucking the same via holes formed in the table device, which is a common practice.
When an ink-jet method is employed in an industrial process, a problem is encountered in that a table device tends to have a significant amount of electrostatic charge because the distance between a nozzle (head) for discharging fluid and a substrate or the like must be set to be less than that in the case of a printer for home use, and because a porous body included in the table device is not made of metal. When the accumulated electrostatic charge is discharged, there is a risk that electronic circuits formed on the substrate may be broken, or flammable solvent included in the liquid may ignite. In order to solve these problems, a method is known in which a so-called ionizer, which is a device for dissipating electrostatic charge, is employed, and also another method is known, in which a table device is formed using a conductive material so that accumulation of electrostatic charge is prevented.
However, such a device for dissipating electrostatic charge may not be sufficiently capable of dissipating the electrostatic charge. In addition, because the latter technique aims to hold relatively hard substrates such as semiconductor wafers or the like, the diameter of the holes formed in the table device is relatively large; therefore, when a so-called flexible substrate, e.g., a thin plastic film or a film-shaped flexible substrate, is chucked, the substrate tends to have chucking marks. When a substrate has chucking marks, it has a deleterious effect in forming and drying of luminescent layers, and problems are encountered in that it is difficult to form a uniform layer, which leads to uneven luminescence and short-circuiting in patterned circuits.